The Grand Canyon in Arizona is called the eighth wonder of the world, and not only because of the grandiose cosmic landscape. At the beginning of the twentieth century, an astonishing discovery was made here that could change all ideas about world history and culture. Why does the scientific community still stubbornly ignore such a sensational fact? Is there some secret being hushed up here? In search of answers to these questions, amateur archaeologist Nolan Moore and his team follow in the footsteps of a 1909 expedition to this mysterious place, and in the end luck smiles on the daring explorers. The find exceeds all expectations. But it is not without reason that the Indian legend says that the god Maaso, the guardian of death, lives in one of the caves of the Grand Canyon. Any person who encroaches on the safety of an ancient secret awaits death in an underground labyrinth inhabited by mysterious creatures... For the first time in Russian!